A conventional seat for an occupant of a vehicle includes a cushion portion and a backrest portion. The cushion portion of the seat is attached to the vehicle body, generally through rails. The cushion portion of the seat supports the backrest portion of the seat. In many conventional designs, a pivot mechanism attaches the backrest portion to the cushion portion and enables pivotal movement of the backrest portion of the seat relative to the cushion portion in both a forward and rearward direction.
During a rear impact to the vehicle, relative movement between the occupant and the vehicle results in a force being applied by the occupant against the backrest portion of the seat. In order to restrain the occupant in the seat during the rear impact, the pivot mechanism of the seat must resist movement of the backrest portion of the seat relative to the cushion portion of the seat in response to the force applied by the occupant against the backrest portion of the seat.
The force applied by the occupant against the backrest portion of the seat results in a torque about the pivot mechanism that tends to rotate the backrest portion of the seat rearward relative to the cushion portion of the seat. The occupant loading can overwhelm the seat structure or the seat latch assembly associated with the pivot mechanism.
In other conventional designs, the backrest portion of the seat is fixed relative to the cushion portion. During a rear impact to the vehicle, relative movement between the occupant and the vehicle results in a force being applied by the occupant against the backrest portion of the seat. In order to restrain the occupant in the seat during the rear impact, the frame of the seat must resist movement of the backrest portion of the seat relative to the cushion portion of the seat in response to the force applied by the occupant against the backrest portion of the seat.
The force applied by the occupant against the backrest portion of the seat results in a torque that tends to bend the frame of the seat allowing the backrest portion of the seat to move rearward relative to the cushion portion of the seat.
It would be desirable, therefore, to find a technique for effectively supporting the backrest portion of a seat relative to a cushion portion of a seat during a rear impact to the vehicle.